Fandom Terms Explained: What OC, AU, Canon, Isekai and OTP Mean

See the terms in a story

The quickest way to learn isekai, villainess and slow burn is to play one. In He Swears He Will Never Love You, you wake up remembering that you are the villainess of a novel you once read (isekai), married to a duke the novel's canon gives to someone else, and every warm word from him has to be earned (slow burn). Open the Story, choose Enter, type the name you want to be called and write your first line. Your first 20 turns are free in your browser, with no sign-up.

Fandom terms at a glance

Fandom terms from A to Z

What does AU mean?

AU stands for alternate universe: a story that takes characters from an existing work and puts them in a different setting, timeline or set of circumstances. Favorites include the coffee shop AU, the modern AU and the royalty AU; a canon divergence AU changes one event and follows what happens next. Outside fandom, Au is the chemical symbol for gold and AU also abbreviates the astronomical unit.

Example: "It's a coffee shop AU where the rival knights run cafés on the same street."

Teasa's Stories are original, so there is no canon to rewrite, but many play like a favorite AU: try Slice of Life for everyday settings or Royalty & Nobility for courts and crowns.

What does canon mean?

In fandom, canon is everything the original work officially establishes: its events, characters, relationships and rules. Anything fans add is non-canon, and fans argue about what counts, such as whether an author's interviews are canon. Outside fandom, a canon is also a body of works accepted as authoritative, or a church law. On TikTok, calling something a "canon event" borrows from Spider-Man: Across the Spider-Verse: it's a painful or embarrassing experience you joke that everyone has to live through.

Example: "It's canon that they grew up together; it's in the first chapter."

When you build your own world, a lorebook keeps its canon straight for every scene.

What is a dere?

A dere type describes how a character acts when they're in love, from Japanese deredere, meaning lovestruck: a tsundere hides it behind insults, a yandere turns possessive and a kuudere stays calm.

Example: "He's a total kuudere: three words a day, but he always remembers your coffee order."

The dere types guide explains every type, and the dere type quiz finds yours.

What is fanfiction?

Fanfiction, or fan fiction, is a story written by fans using characters, settings or events from an existing book, show, game or other work. It is usually unofficial and shared for free on archives such as Archive of Our Own (AO3), Wattpad and FanFiction.Net, and it ranges from a few lines to novel length.

Example: "I read a fanfiction where the side character finally gets her own adventure."

Teasa's Stories are original interactive fiction rather than fan fiction of existing franchises: you play the main character and the cast answers what you write. Fans of reader-insert fic will feel at home; the Y/N guide explains how the two compare.

What does fanon mean?

Fanon is an idea about a story that so many fans share it feels official, even though the source never says it. A fanon detail can start in one popular fic and spread until newcomers assume it's canon.

Example: "It's fanon that the knight can't cook. The books never mention food at all."

What does headcanon mean?

A headcanon is your personal belief about a story that the source neither confirms nor contradicts. It becomes fanon if enough fans adopt it.

Example: "My headcanon is that the stoic general bakes bread when he can't sleep."

On Teasa, your headcanon can become canon for a Character of your own: write it into their personality when you create a Character.

What does isekai mean?

Isekai (異世界, "another world") is a Japanese fantasy genre in which the main character is transported to, summoned into or reborn in another world, often a fantasy realm, a game or the pages of a novel. Fans also use it as a verb: "I got isekai'd." A reverse isekai brings someone from a fantasy world into ours.

Example: "It's an isekai: she dies in a car crash and wakes up as a duke's daughter."

Play one in the Isekai & Reincarnation collection, or meet anime-style isekai Characters in the anime AI chat guide.

What does kin mean?

In fandom spaces, kin (short for fictionkin) means identifying strongly with a fictional character, sometimes as part of a person's sense of self. In casual use it's lighter: "I kin her" just means "I relate to her completely."

Example: "I kin every tired older sister in fiction."

What is a Mary Sue?

A Mary Sue is a character who is unrealistically talented, beloved and flawless, often read as the author's idealized stand-in. The name comes from a 1973 parody story by Paula Smith that mocked idealized heroines in Star Trek fan fiction; a male version is sometimes called a Gary Stu.

Example: "She's a Mary Sue: she aced the exam, tamed the dragon and everyone falls for her by chapter two."

A character becomes interesting when something stands in their way. The free OC maker asks for a goal and an obstacle, and the character card guide shows how to give a character limits and a voice.

What does OC mean?

OC means original character: a character you invent rather than one from an existing work, whether you place them in a fan story or a world of your own. Outside fandom, OC can also mean overclocking a computer or Orange County, California.

Example: "This is my OC, a disgraced court mage who sells fortunes at the night market."

Build yours with the free OC maker, name them with the fantasy name generator or the Japanese name generator, then create them on Teasa and chat with them.

What does OOC mean?

OOC means out of character: in roleplay it marks a note from the player rather than the character, and in fan fiction it describes a character acting unlike their canon self.

Example: "(OOC: let's skip to the next morning.)" or "The villain apologizing felt so OOC."

The AI roleplay terms glossary covers OOC and the other words you'll meet in AI roleplay.

What does otome mean?

Otome (乙女, "maiden") describes romance games and stories written for women, in which you play the heroine and choose between several love interests, each with their own route.

Example: "In the otome game, every route ends differently depending on who you spend your evenings with."

The AI otome game guide turns that format into Stories you play in your own words.

What does OTP mean?

OTP stands for one true pairing: the couple a fan loves above every other. A favorite trio is an OT3.

Example: "The rival knights are my OTP. Nobody else comes close."

Find a pairing worth the title in Enemies to Lovers or Friends to Lovers.

What does POV mean?

POV means point of view, the character whose eyes a scene is told through; in fan fiction a chapter headed "Kai's POV" switches the narration to Kai. On TikTok and Reels, a video captioned "POV:" is a short skit filmed as if you, the viewer, are in the scene, such as "POV: you're the new student and the class president already dislikes you."

Example: "Chapter three is in his POV, so you finally hear what he was thinking."

Teasa Stories are told to you in the second person, so you're always the POV character: you decide what you say and do.

What is regression in manhwa and webnovels?

Regression is a genre in which the main character goes back to an earlier point in their own life, often after dying, keeping every memory of how things went wrong. The hero is called a regressor, and the story is about using that second chance.

Example: "She regressed to the day before the engagement and swore she'd never marry him again."

Play it in Regression & Second Chances at Life, starting with After the Regression, He Dotes: you drowned believing your husband never loved you, and now you're back in the carriage on the day it all began.

What does RP mean?

RP means roleplay: telling a story together, with each person writing as a character, in chat, on a forum or with an AI. People who do it are RPers. Outside fandom, RP also stands for Received Pronunciation, the standard British accent.

Example: "Want to RP? You play the rogue, I'll play the guard who catches you."

Start a roleplay with AI Characters in the AI chat roleplay guide, and learn turns, branching and openings in the AI roleplay guide.

What is a self-insert?

A self-insert is a character who stands in for the writer, written into the story as themselves or a thinly veiled version. A reader-insert does the same for you, the reader.

Example: "The new transfer student is obviously the author's self-insert."

The Y/N guide explains self-insert, reader-insert and how AO3 tags them.

What does shipping mean?

Shipping, from relationship, means wanting two characters to be in a romantic relationship, whether or not the story puts them together; the couple is your ship. When the source makes it official, fans say the ship is canon.

Example: "I've shipped them since the first episode, and now it's canon."

Choose your own ship in Love Triangle & Multiple Love Interests, where more than one Character is drawn to you.

What does slow burn mean?

A slow burn is a romance in which feelings build gradually through tension, restraint and small moments, long before anyone confesses. Outside fandom, a slow burn can also mean anger that builds slowly.

Example: "It's a 200,000-word slow burn. They don't hold hands until chapter forty."

Feel it in Slow Burn Romance, where every milestone with a Character is earned scene by scene.

What is a villainess story?

A villainess story is a romance-fantasy in which the heroine wakes up as the villain of a novel or otome game, knows her doomed ending, and sets out to change it. It's popular in Korean and Japanese webnovels and manhwa, and often overlaps with isekai and regression.

Example: "In this villainess manhwa, she reads ahead in her own novel and avoids every trap."

Play one in Villainess, including The Villainess You Asked For, where you're reborn as the hated villainess of your favorite otome game.

What does x reader mean?

X reader means a story that pairs a character with you, the reader, as in "Character x Reader". These stories use Y/N, "your name", as a blank where your own name goes.

Example: "It's a knight x reader one-shot, and Y/N is the princess he's sworn to guard."

The Y/N guide covers L/N, E/C and the rest of the shorthand.

Read one fan post through seven terms

Here is a post of the kind you might see on any fan forum, written for this guide:

My OTP isn't canon yet and the slow burn is killing me. Fanon says he's heartless; my headcanon is that he just doesn't know how to be gentle. Writing a coffee shop AU tonight with my OC as the barista who sees through him.

• OTP: the writer's favorite couple.
• Canon: the source hasn't made them a couple.
• Slow burn: the story is taking its time getting there.
• Fanon: most fans read him as heartless, though the source never says so.
• Headcanon: the writer's personal reading of him.
• AU: a story that moves the characters into a café.
• OC: a character the writer invented to join them.

FAQ

What does fandom mean?

A fandom is the community of fans around a book, show, game or band, together with everything they make and share about it, from fan fiction and fan art to theories and in-jokes. Fandom slang is the vocabulary that community uses.

What's the difference between canon, fanon and headcanon?

Canon is what the original work officially establishes. Fanon is what many fans believe without the source confirming it. Headcanon is one person's own belief about the story.

What's the difference between an OC and a self-insert?

An OC is any character you invent. A self-insert is a character who stands in for the writer, and a reader-insert stands in for you, the reader, usually in second person with Y/N.

What's the difference between isekai and regression?

Isekai sends someone into another world, through rebirth, a summons or a portal. Regression sends someone back to an earlier point in their own life with their memories, to live it differently. Many villainess stories combine the two.

What does it mean when a ship becomes canon?

It means the official story confirms the relationship fans were hoping for: the couple gets together in the source itself, not only in fan works.

Where can I play a story with these tropes?

On Teasa. The Isekai & Reincarnation, Regression, Villainess and Slow Burn Romance collections each open on a scene where you play the main character, and your first 20 turns are free in your browser with no sign-up. A free account keeps your Stories and adds free, unlimited DMs with any Character.

Sources

Checked on 17 October 2026.

• Dictionary.com: headcanon, fanon, canon, OTP, ship, Mary Sue and isekai.
• Aja Romano, Canon, fanon, shipping and more: a glossary of the tricky terminology that makes up fan culture, Vox, 7 June 2016.
• Wikipedia: Fan fiction, Mary Sue, Isekai, Original character, Otome game and Self-insertion.